1. Field of Invention
The present invention relates to a substrate inspection device and a substrate inspection method for inspecting a manufactured glass or plastic substrate used for a display panel, and particularly to a substrate inspection device and a substrate inspection method for inspecting defect on a substrate in a production line of a glass or plastic substrate or in a production line of a display panel substrate using the glass or plastic substrate.
2. Description of Related Art
A thin film transistor (TFT) substrate, a color filter substrate for a display panel of a liquid crystal display device, a substrate for a plasma display panel or a substrate for an electroluminescence (EL) display panel is manufactured by a photolithography technology, in which patterns are formed on a substrate such as a glass or plastic substrate. At this time, if a scratch or a foreign matter is present on the substrate, the patterns cannot be formed in the most optimum form and adverse effects are resulted. Accordingly, a substrate inspection device is required to use for inspecting defect on a substrate, such as a scratch or a foreign matter.
The substrate inspection device uses an inspection light such as a laser light to irradiate a substrate and receives a reflected or scattered light from the substrate, so as to inspect defect on the substrate such as a scratch or a foreign matter. The inspection of the entire substrate by scanning the substrate with the inspection light is time-consuming. Therefore, the defect on a substrate cannot be inspected with the conventional substrate inspection device in real time in a production line of a glass or plastic substrate or in a production line of a display panel substrate using the glass or plastic substrate. Accordingly, JP Patent Publications No. 2005-164558 discloses a particle inspection method for a glass substrate, in which each glass substrate is scanned with an in-line camera, and the information obtained on particles in a local unit area is quantified, and the statistical value of information of the particle for the whole area of each glass substrate is presented.
The technology reported by JP Patent Publications No. 2005-164558 is to determine if the sum of area of each scanned unit area of the glass substrate is close to and within a tolerance area of one glass substrate (step (e) of claim 1 and S51 of FIG. 4 of the JP Patent Publications No. 2005-164558). When the result is determined as “no”, return to the previous step. When the result is determined as “yes”, information in the scanned unit areas is collected and added up as the information of one substrate and stored as particle information data for the whole area of the glass substrate (step (f) of claim 1 and S50 of FIG. 4). Thereafter, whether the number of particle of the information on particle for the whole area of the glass substrate is greater than or equal to a predetermined number is determined (S80 of FIG. 4). If the number of particle is greater than or equal to the predetermined number, an alarm is sent (S90 of FIG. 4) to stop the processing. Therefore, in the technology reported by JP Patent Publications No. 2005-164558, after scanning multiple times to achieve the sum of area of the unit areas being close to the tolerance area of one glass substrate, one particle information for the whole area of the glass substrate is obtained. It is required to repeat again the same number of scanning for obtaining the next particle information. Accordingly, there are problems, for example, the speed of information low, and the identification of problems is delayed.